package org.shop.weixin.util;

import java.io.InputStream;
import java.io.Writer;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;

import org.shop.weixin.message.resp.Article;
import org.shop.weixin.message.resp.ImageMessage;
import org.shop.weixin.message.resp.MusicMessage;
import org.shop.weixin.message.resp.NewsMessage;
import org.shop.weixin.message.resp.TextMessage;
import org.shop.weixin.message.resp.VideoMessage;
import org.shop.weixin.message.resp.VoiceMessage;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.core.util.QuickWriter;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
import com.thoughtworks.xstream.io.xml.XppDriver;

/**
 * 消息处理工具类
 * 
 * @author manailin
 * @date 2013-09-15
 */
public class MessageUtil {
    // 请求消息类型：文本
    public static final String REQ_MESSAGE_TYPE_TEXT     = "text";
    // 请求消息类型：图片
    public static final String REQ_MESSAGE_TYPE_IMAGE    = "image";
    // 请求消息类型：语音
    public static final String REQ_MESSAGE_TYPE_VOICE    = "voice";
    // 请求消息类型：视频
    public static final String REQ_MESSAGE_TYPE_VIDEO    = "video";
    // 请求消息类型：地理位置
    public static final String REQ_MESSAGE_TYPE_LOCATION = "location";
    // 请求消息类型：链接
    public static final String REQ_MESSAGE_TYPE_LINK     = "link";

    // 请求消息类型：事件推送
    public static final String REQ_MESSAGE_TYPE_EVENT    = "event";

    // 事件类型：subscribe(订阅)
    public static final String EVENT_TYPE_SUBSCRIBE      = "subscribe";
    // 事件类型：unsubscribe(取消订阅)
    public static final String EVENT_TYPE_UNSUBSCRIBE    = "unsubscribe";
    // 事件类型：scan(用户已关注时的扫描带参数二维码)
    public static final String EVENT_TYPE_SCAN           = "scan";
    // 事件类型：LOCATION(上报地理位置)
    public static final String EVENT_TYPE_LOCATION       = "LOCATION";
    // 事件类型：CLICK(自定义菜单)
    public static final String EVENT_TYPE_CLICK          = "CLICK";

    // 响应消息类型：文本
    public static final String RESP_MESSAGE_TYPE_TEXT    = "text";
    // 响应消息类型：图片
    public static final String RESP_MESSAGE_TYPE_IMAGE   = "image";
    // 响应消息类型：语音
    public static final String RESP_MESSAGE_TYPE_VOICE   = "voice";
    // 响应消息类型：视频
    public static final String RESP_MESSAGE_TYPE_VIDEO   = "video";
    // 响应消息类型：音乐
    public static final String RESP_MESSAGE_TYPE_MUSIC   = "music";
    // 响应消息类型：图文
    public static final String RESP_MESSAGE_TYPE_NEWS    = "news";

    /**
     * 解析微信发来的请求（XML）
     * 
     * @param request
     * @return Map<String, String>
     * @throws Exception
     */
    @SuppressWarnings("unchecked")
    public static Map<String, String> parseXml(HttpServletRequest request) throws Exception {
        // 将解析结果存储在HashMap中
        Map<String, String> map = new HashMap<String, String>();

        // 从request中取得输入流
        InputStream inputStream = request.getInputStream();
        // 读取输入流
        SAXReader reader = new SAXReader();
        Document document = reader.read(inputStream);
        // 得到xml根元素
        Element root = document.getRootElement();
        // 得到根元素的所有子节点
        List<Element> elementList = root.elements();

        // 遍历所有子节点
        for (Element e : elementList)
            map.put(e.getName(), e.getText());

        // 释放资源
        inputStream.close();
        inputStream = null;

        return map;
    }

    /**
     * 扩展xstream使其支持CDATA
     */
    private static XStream xstream = new XStream(new XppDriver() {
                                       @Override
                                       public HierarchicalStreamWriter createWriter(Writer out) {
                                           return new PrettyPrintWriter(out) {
                                               // 对所有xml节点的转换都增加CDATA标记
                                               boolean cdata = true;

                                               @Override
                                               @SuppressWarnings("unchecked")
                                               public void startNode(String name, Class clazz) {
                                                   super.startNode(name, clazz);
                                               }

                                               @Override
                                               protected void writeText(QuickWriter writer,
                                                                        String text) {
                                                   if (cdata) {
                                                       writer.write("<![CDATA[");
                                                       writer.write(text);
                                                       writer.write("]]>");
                                                   } else {
                                                       writer.write(text);
                                                   }
                                               }
                                           };
                                       }
                                   });

    /**
     * 文本消息对象转换成xml
     * 
     * @param textMessage 文本消息对象
     * @return xml
     */
    public static String messageToXml(TextMessage textMessage) {
        xstream.alias("xml", textMessage.getClass());
        return xstream.toXML(textMessage);
    }

    /**
     * 图片消息对象转换成xml
     * 
     * @param imageMessage 图片消息对象
     * @return xml
     */
    public static String messageToXml(ImageMessage imageMessage) {
        xstream.alias("xml", imageMessage.getClass());
        return xstream.toXML(imageMessage);
    }

    /**
     * 语音消息对象转换成xml
     * 
     * @param voiceMessage 语音消息对象
     * @return xml
     */
    public static String messageToXml(VoiceMessage voiceMessage) {
        xstream.alias("xml", voiceMessage.getClass());
        return xstream.toXML(voiceMessage);
    }

    /**
     * 视频消息对象转换成xml
     * 
     * @param videoMessage 视频消息对象
     * @return xml
     */
    public static String messageToXml(VideoMessage videoMessage) {
        xstream.alias("xml", videoMessage.getClass());
        return xstream.toXML(videoMessage);
    }

    /**
     * 音乐消息对象转换成xml
     * 
     * @param musicMessage 音乐消息对象
     * @return xml
     */
    public static String messageToXml(MusicMessage musicMessage) {
        xstream.alias("xml", musicMessage.getClass());
        return xstream.toXML(musicMessage);
    }

    /**
     * 图文消息对象转换成xml
     * 
     * @param newsMessage 图文消息对象
     * @return xml
     */
    public static String messageToXml(NewsMessage newsMessage) {
        xstream.alias("xml", newsMessage.getClass());
        xstream.alias("item", new Article().getClass());
        return xstream.toXML(newsMessage);
    }
}
